Individually packaged disposable absorbent articles, such as individually packaged sanitary napkins, are known in the art. Individually packaged sanitary napkins provide the advantage that they are compact (e.g., they can be conveniently carried in a consumer's pocket or purse). Individually packaged sanitary napkins also resist soiling of the sanitary napkin prior to use, while the sanitary napkin is being carried by the consumer. U.S. Pat. No. 4,556,146 issued Dec. 3, 1985 to Swanson et al. discloses an individually packaged disposable absorbent article having an absorbent pad and a protective wrapper. The absorbent pad and wrapper are folded as unit about two fold-axes, and longitudinal flaps of the wrapper are frangibly sealed, such as by heat sealing.
U.S. Pat. No. 5,181,610 issued Jan. 26, 1993 to Quick et al. discloses a pouch for packaging sanitary napkins. The side seams of the pouch are formed by the application of heat in combination with mechanical deformation of two or more layers of the pouch. Embossing plates having different embossing patterns including a dot pattern, a parallel line pattern, and a criss-crossed line pattern are disclosed. Quick et al. discloses that the pouch side seams can be made so that the pouch is opened by peeling apart the seams, or so that the seams are sealed so tightly that the pouch can be opened only by tearing the pouch material.
While the prior art provides seals for individually wrapped sanitary napkins, the Applicants of the present invention have recognized that known seals have inherent disadvantages, especially when individually wrapped sanitary napkins are produced on high speed production lines. During assembly and packaging on high speed production lines, the individually wrapped sanitary napkins can be compressed. Such compression can cause air trapped within wrapper to "blow out" the seals along the edge of the wrapper. "Blown" seals are undesirable because they permit contamination of the sanitary napkin within the wrapper, and present a low quality appearance to the consumer.
Blown seals can be prevented by uniformly increasing the seal strength. Unfortunately, uniformly increasing seal strength is not an acceptable solution. High seal strength can cause the wrapper edges to tear on opening, rather than smoothly peeling apart. Tearing of the wrapper edge is not consumer preferred because tearing of the wrapper edge is relatively difficult, noisy, and indiscreet. Torn wrapper edges also present a low quality appearance to the consumer. As a result, manufacturers of individually packaged sanitary napkins have been forced to trade off between relatively low strength wrapper seals which can open prematurely and permit contamination of the sanitary napkin prior to use, and relatively high strength wrapper seals which require tearing of the wrapper.
Accordingly, it is an object of the present invention to provide an individually packaged disposable absorbent article having a releasable package seal.
It is another object of the present invention to provide an individually packaged disposable absorbent article having a releasable package seal which permits peeling of the seal, without tearing, in the direction parallel to the edge of the package and resists bursting of the package seal in the direction perpendicular to the edge of the package.
A further object of the present invention is to provide an individually packaged disposable absorbent article comprising a package having thermoplastic film layers joined at a releasable seal along an edge of the package, the releasable seal comprising an array of discrete thermal-mechanical bonds, and the seal having a ratio of the bond width to bond spacing as measured in a direction perpendicular to the package edge which is less than the ratio of bond width to bond spacing as measured in a direction parallel to the package edge.